1. Field of the Invention
The present invention relates to an apparatus and a method of generating ultrasonic vibration, and an apparatus and a method of cleaning a wafer using the same. More particularly, the present invention relates to an apparatus and a method of applying ultrasonic vibration to a cleaning solution for cleaning a wafer, and an apparatus and a method of cleaning the wafer using the same.
2. Description of the Related Art
Generally, semiconductor devices are manufactured by repeatedly performing unit processes. The unit processes include a deposition process, a photolithography process, an etching process, a chemical and mechanical polishing process, a cleaning process, a drying process, etc. In the cleaning process, particles and unnecessary layers formed on the wafer during the above unit processes are removed from the wafer. Recently, as a pattern formed on the wafer is gradually shrunk and the aspect ratio of the pattern is gradually increased, the cleaning process becomes much more important.
Conventionally, an apparatus for cleaning a wafer includes a cleaning solution provider for providing a cleaning solution onto the wafer and an ultrasonic vibrator for applying an ultrasonic vibration to the clean solution.
The ultrasonic vibrator merely transmits the ultrasonic vibration without any variation in the intensity and direction of the ultrasonic vibration. Therefore, when the intensity of the ultrasonic vibration is non-uniform, the wafer may be non-uniformly cleaned by the ultrasonic vibration.
Further, when the cleaning solution is not distributed on the wafer to a sufficient thickness and the ultrasonic vibration applied to the wafer has an excessively high intensity, there is a problem in that the ultrasonic vibration may cause significant damage to the pattern on the wafer.